Minor leaks in liquid containers set into or under the ground surface are extremely difficult to detect. The rate of fluid loss is often slow and variable, particularly if the leak is above the average low liquid level. Also, changes due to natural causes, such as thermal expansion and contraction and evaporation will affect the rate of fluid loss. Frequently, several hundreds of gallons in larger containers must be lost over a period of weeks before the loss is detected. Upon recognition of the problem, costly probing or excavation is generally required in order to actually locate the leak.
As the value of the liquid in question increases, or where the local ecology may be endangered by such leakage it becomes increasingly important to quickly and accurately locate the source of fluid loss. Currently known detection methods are often costly and disruptive of normal operations in the use of storage containers. Some methods, such as the use of radioactive trace materials, introduce their own hazards and are, in any event, useful only when a leak is suspected.
It is therefore an object of this invention to provide a leak detection method for subterranean fluid storage containers which will overcome the disadvantages associated with prior art techniques.
It is an object of the invention to provide a system and method for detecting leaks which is both reliable and economical.
It is a further object of the invention to provide such a detection system which will also enable one to locate the approximate position of a detected leak.
Yet another object of the invention is to provide a leak detection method which is neither harmful to the ecology nor disruptive of the normal use of the fluid storage facility.